Method of recovering metals from cables and the like

ABSTRACT

A method for recovering metals from discarded cables and the like wherein the discarded cables are comminuted in a hammer mill and, after removing light components by suction and of iron components by magnetic action, may be additionally comminuted by a cutting action. The comminuted material is successively treated in belt sink separators individually associated with draining screens and conveyors operatively connected therewith for removing floats from the first separator or separators and sinks from the last separator. The several sink separators are operated at different turbidities.

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United States Patent inventors Appl. No.

Filed Patented Assignee Priority Hans Lenz Heiligenhaus;

Jochen Mehlbeer, Wattenscheid; Heinrich Macura, Essen; Otto Weidner, Bochum- Stiepel, all of, Germany .lune 1l, 1968 June l, 1971 Eisen und Metall A G.

Gelsenkirchsen, Ahlmannstof, Germany June l2, 1967, June 13, 1967, May 3, 1968 Germany E34,l65, P l5 58 407.3 and P 17 58 265.9

METHOD OF RECOVERING METALS FROM CABLES AND THE LIKE 6 Claims, 2 Drawing Figs.

U.S. Cl 241/19, 241/20, 241/29 Int. Cl B02c 21/00 [50] Field ofSearch 241/14, 19, 20, 29, 60, 24

[56] References Cited UNITED STATES PATENTS 2,104,709 l/1938 Weinig 241/20 2,965,316 12/1960 Henderson 24l/20X 3,074,653 l/l 963 Schorsch .i 241/60X Primary Examiner-Donald G. Kelly Attorneys-Ernest F. Marmorek, Jordan B. Bierman and Marmorek & Bierman ABSTRACT: A method for recovering metals from discarded cables and the like wherein the discarded cables are comminuted in a hammer mill and, after removing light components by suction and of iron components by magnetic action, may be additionally comminuted by a cutting action. The comminuted material is successively treated in belt sink separators individually associated with draining screens and conveyors operatively connected therewith for removing floats from the rst separator or separators and sinks from the last separator. The several sink separators are operated at different turbidities.

PATENTEDJUN Hem 3,582,004

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METHOD F RECOVERING METALS FROM CABLES AND THE LIKE The invention relates to methods of recovering metals from discarded cables and cable scrap whereby the cables or the cable scrap are opened and comminuted in a hammer mill.

Discarded cables, as ground cables and the like, are usually composed of more than 50 percent by volume of insulating materials, such as synthetic substances, rubber and paper, of the conductor proper, usually copper or aluminum, or armor and cladding of steel and lead. Such cables can be decomposed into their components by means of a hammer mill or by so-called cutting mills. Mechanical sorting of the product of comminution is very difficult because this product, as a whole, is likely to mat and, particularly, the metals which are in the form of more or less long wires and strips tend to bunch.

lt is accordingly among the principal objects of the present invention to provide for an effective and efficient sorting for recovering metals from a product of comminution.

Further objects and advantages of the invention will be set forth in part in the following specification and in part will be obvious therefrom without Abeing specifically referred to, the same being realized and attained as pointed out in the claims hereof.

Broadly speaking, according to the invention the output of a hammer mill is conveyed without intermediate storage to a first sink separator and the intermediate product thereof is directly conveyed to a second sink separator having a different turbidity. If desired, the intermediate product of the second separator is directly conveyed to al third sink separator. The traveling velocitiesto and through the sink separators of the respective products which must be sorted, and of the intermediate product, as long as still at least two metal sorts are contained therein, are so adjusted that the volumetric breaking apart thereof produced by the hammer mill, particularly of the metals to be' recovered, is essentially maintained.

ln the separating practice it is usual to store the comminuted raw input in a buffer bunker in order yto obtain an equalization of the input amountland an equalization of the input composition for the subsequent separating process. The invention departs from these conventional steps and obtains the new result of avoiding matting or bunching of the individual components of the product of the comminution.

ln practice the aforesaid breaking apart obtained by the hammer mill particularly of the metal parts to be recovered is assured by suitable dimensioning of the conveyor belts and their conveying speed, and by the output of the sink separators. Only a thin layer and not a dense heaping should be fonned on the conveyor belts. Damming up and excessive accumulation of the material to be separated must be avoided.

The cables to be broken down usually contain iron parts, for example steel armor, which are suitably separated by subjecting the comminuted material on its way to the first sink separator to the action of a magnetic separator.

ln a preferred embodiment of the invention, suction is provided at the hammer mill outlet. A portion of the dust and mainly fine pieces of insulation, in certain circumstances also paper and the like, are thereby separated ahead of the first part of the separating process.

With a high power, robust hammer mill, a complete breakdown of discarded cable is obtainable, as a rule. Difficulties are experienced, however, when breaking down stranded cables wherein the insulation often separates only incompletely from the conductor which consists of many thin individual wires. ln order to avoid sorting out the stranded cables prior to the separating process, a further development of the invention provides for additional comminution by cutting and/or shearing the comminuted material, if desired, subsequent to the magnetic separation.

Thereby there are obtained not only the breakdown of the stranded cables and of other cables which are difficult to separate, but also an equalization of the size of the individual metal and insulating parts is brought about. Excessively long wires and insulating parts which may disturb the subsequent sorting process are reduced to tolerable lengths.

The comminution of discarded cables and their breakdown by means having a cutting effect only-so-called cutting mills- -has been successfully tried. lt must, however, be considered that the cables may contain a steel armor which may amount to 25 percent by weight, and therefore the cutting comminuting apparatus and primarilyv the parts subject to wear must be designed to meet these aggravating conditions. With the method according to the invention, the input of the cutting mill is already free of iron, so that wear is reduced.

ln a further embodiment of the invention, the floats of the first separator which contain one of the metals to be recovered, for example, aluminum, are subjected to a second sink separation at less turbidity.

The last-mentioned embodiment of the invention deviates from the conventional methods of floating and separating at first the main component of the material to be separated, namely the light, insulating substances in the first heavy medium separator at less turbidity, for example about 2 grams per cubic centimeter. The method according to the invention separates at first at a turbidity of, for example 2.8 grams per cubic centimeter the input material into two components, the floats consisting of insulating material and aluminum. lt is thereby avoided that later on aluminum and copper wir'e pieces bunch together when sinking in the separator, and being removed therefrom, respectively, and that the irregularly formed bent copper wire pieces which tend to compact, clamp the aluminum wires.

A plant or other apparatus for sorting comminuted cables according to the invention comprises a suction device that is placed at the outlet of a hammer mill, a conveyor receiving the output of the hammer mill, a magnetic separator acting on the comminuted material and positioned adjacent the conveyor, a first belt sink separator supplied by the conveyor for separating the light components, a second belt sink separator receiving the sinks of the first belt sink separator, a drainage screen with conveyor belt being associated with each of the two belt sink separators for receiving the floats, and a drainage screen and a conveyor belt additionally being associated with the second belt sink separator for receiving sinks therefrom.

lnsulating material, aluminum, copper and lead may be received by the first belt sink separator. The insulating material is separated as floats at a turbidity of about 2.0 grams per cubic centimeter. Aluminum floats up in the second belt sink separator at a turbidity of 2.8 to 3 grams per cubic centimeter.

The remaining sinks still contain copper and lead which may be separated by hand on a subsequent picking belt. ln lieu of belt sink separators, other sink separators, for example drum sink float separators may be used.

ln a further development of the invention a cutting or shearing comminuting apparatus having rotating knives follows the conveyor belt which receives the output of the hammer mill.

The novel features which are considered characteristic of the invention are set forth with particularity in the appended claims. The invention itself, however, and additional objects and advantages thereof will best be understood from the following description of embodiments thereof when read in connection with the accompanying drawings, wherein:

v F lG. l is a diagrammatic illustration of a plant for performing the method according to the invention; and

FIG. 2 is a diagrammatic illustration of a modified plant according to the invention.

Referring more particularly to FIG. l of the drawing, a feeder belt l transports raw material to a hammer mill 2. The material comminuted in the hammer mill 2 is placed on a conveyor belt 4. A large portion of the fine and light components is sucked of by a suction device'3. A lifting magnet 5 is placed at the end of the conveyor belt d for extracting iron pieces. The material which is now free of dust and iron parts is supplied to a first belt sink separator 6, the turbidity of which is so adjusted that the insulating material floats up. lt is rinsed off on a draining screen l2 and removed on a conveyor belt 13. The sinks of the first separator 6 are divided into aluminum and copper in a second belt sink separator'7. The floating aluminum arrives at a conveyor belt lll by way of a draining screen the heavy copper arrives at a conveyor belt 9 by means of a draining screen 8.

FIG. 2 shows a second embodiment of the invention, like parts being designated by like numerals in both Figures. Referring to FIG. 2, the material which is free of dust and iron is fed into a comminuting apparatus 14 having rotating knives, before the material is fed into the belt sink separator 6. Thereafter, the additionally broken up and comminuted material is treated in and conducted through a plant identical with the plant shown in FIG. l and described above.

We wish it to be understood that we do not desire to be limited to the exact details of construction shown and described, for obvious modifications will occur to a person skilled in the art.

Having thus described the invention, what we claim as new and desire to be secured by Letters Patent, is as follows:

1. In a method of recovering metal from discarded cables and the like composed of several metals wherein the cables are comminuted in a mill the steps comprising conducting the output of the mill directly into a first sink separator, conducting at least a portion of the output of the first sink separator directly into a second sink separator with a turbidity different from the turbidity of the first sink separator, and so adjusting the travel velocities, to and through the sink separators of the respective product to be separated, at least as long as there are at least two metal sorts in the product, that the separating effected in the mill is substantially maintained by said sink separators.

2. In a method as defined in claim l wherein the comminuted material is subjected to magnetic separation prior to the first sink separation.

3. In a method according to claim 2 wherein the comminuted material before the first sink separation is further comminuted by cutting after being subjected to magnetic separation.

4. In a method according to claim l wherein the comminuted material is further comminuted by cutting before the first sink separation.

5. In a method as defined in claim l wherein the output of the mill is subjected to suction for separating fine and light components.

6. In a method as defined in claim 1 wherein the floats of the first sink separation containing one of the metals to be recovered, are subjected at reduced turbidity to the second sink separation. 

1. In a method of recovering metal from discarded cables and the like composed of several metals wherein the cables are comminuted in a mill the steps comprising conducting the output of the mill directly into a first sink separator, conducting at least a portion of the output of the first sink separator directly into a second sink separator with a turbidity different from the turbidity of the first sink separator, and so adjusting the travel velocities, to and through the sink separators of the respective product to be separated, at least as long as there are at least two metal sorts in the product, that the separating effected in the mill is substantially maintained by said sink separators.
 2. In a method as defined in claim 1 wherein the comminuted material is subjected to magnetic separation prior to the first sink separation.
 3. In a method according to claim 2 wherein the comminuted material before the first sink separation is further comminuted by cutting after being subjected to magnetic separation.
 4. In a method according to claim 1 wherein the comminuted material is further comminuted by cutting before the first sink separation.
 5. In a method as defined in claim 1 wherein the output of the mill is subjected to suction for separating fine and light components.
 6. In a method as defined in claim 1 wherein the floats of the first sink separation containing one of the metals to be recovered, are subjected at reduced turbidity to the second sink separation. 